Time series evaluation of condemnation at poultry slaughterhouses enable to export in Southeastern Brazil (2009-2019): a tool for optimizing resources in the poultry production chain.

BACKGROUND: Even with the technological advances in management, health and genetics applied to poultry farming worldwide, there is still a high rate of carcasses condemnation at slaughterhouses, which result in losses for the poultry production chain. Thus, this work aimed to evaluate the condemnation occurrence index (COI) and adjusted seasonal index (ASI) of poultry (turkey, griller, and heavy chicken) between 2009 and 2019, in a slaughterhouse enable to export in southeastern Brazil. Data were obtained from official spreadsheets from the Brazilian Federal Inspection Service (FIS) and used to calculate the COI, correlation analysis between the main causes of condemnation, and ASI assessments throughout the year. RESULTS: Seven percent (55,594,318) of the poultry carcasses were condemned (partial or total), and the most frequent causes, contamination, and contusion/traumatic injury, amounted to 63.5% of the total condemnation. There was a trend of increasing condemnation throughout the time series evaluated, with COI varying between 45,282-149,809 condemnations per 1,000,000 poultry slaughtered. Considering the ASI, it was identified that for ascitic syndrome, July has a higher index value (1.63) than the months between January-June (P < 0.05). CONCLUSIONS: The main causes of condemnation were contamination and contusion/traumatic injury, both technological causes. ASI showed that in July there is a greater carcasses condemnation due to ascitic syndrome than in the months between January and June. The variations observed in the ASIs can provide subsidies for preventive measures and optimization of human and financial resources, generating positive impacts on food safety, productivity, and profitability of the sector.

Serotypes and Pulsotypes diversity of Listeria monocytogenes in a beef-processing environment.

Utensils and equipment from meat-processing facilities are considered relevant cross-contamination points of Listeria monocytogenes to foods, demanding tracking studies to identify their specific origins, and predict proper control. The present study aimed to detect L. monocytogenes in a beef-processing facility, investigating the diversity of serotypes and pulsotypes in order to identify the possible contamination routes. Surface samples from knives (n=26), tables (n=78), and employees hands (n=74) were collected before and during the procedures from a beef-processing facility, in addition to surface samples of end cuts: round (n=32), loin (n=30), and chuck (n=32). All samples were subjected to L. monocytogenes screening according ISO 11.290-1, and the obtained isolates were subjected to serotyping and pulsed-field gel electrophoresis. Listeria spp. were identified in all processing steps, in 61 samples, and L. monocytogenes was detected in 17 samples, not being found only in knives. Eighty-five isolates were identified as L. monocytogenes, from serotypes 1/2c (n=65), 4b (n=13), and 1/2b (n=7), being grouped in 19 pulsotypes. Considering these results, cross-contamination among hands, tables, and beef cuts could be identified. The obtained data indicated the relevance of cross-contamination in the beef-processing facility, and the occurrence of serotypes 1/2b and 4b in beef cuts distributed for retail sale is a public health concern.

Multi-locus sequence typing, antimicrobials resistance and virulence profiles of Salmonella enterica isolated from bovine carcasses in Minas Gerais state, Brazil.

The aim of this study was to identify virulence and antimicrobial resistance profiles and determine the sequence type (ST) by multilocus sequence typing (MLST) of Salmonella enterica isolates from bovine carcasses from slaughterhouse located in Minas Gerais state, Brazil, and its relationship with bovine isolates obtained on the American continent based on sequence type profile. The MLST results were compared with all Salmonella STs associated with cattle on American continent, and a multi-locus sequence tree (MS tree) was built. Among the 17 S. enterica isolates, five ST profiles identified, and ST10 were the most frequent, grouping seven (41.2%) isolates. The isolates presented 11 different profiles of virulence genes, and six different antibiotics resistance profiles. The survey on Enterobase platform showed 333 Salmonella STs from American continent, grouped into four different clusters. Most of the isolates in the present study (13/17), were concentrated in a single cluster (L4) composed by 74 STs. As a conclusion, five different STs were identified, with ST10 being the most common. The isolates showed great diversity of virulence genes and antibiotics resistance profiles. Most of the isolates of this study were grouped into a single cluster composed by 74 STs formed by bovine isolates obtained on the American continent.

Prevalence of cysticercosis in cattle slaughterhouses in the western region of Minas Gerais, Brazil (2013-2020): Influence of sanitary regulations in reducing risks to human health.

Bovine cysticercosis is a foodborne zoonosis that has a worldwide distribution, and its highest prevalence is found in developing countries with a large volume of cattle production, such as Brazil. The objective was to evaluate the prevalence of cysticercosis during seven years in three slaughterhouses located in the western region of Minas Gerais state, Brazil, and the impacts of the legislation on the identification and destination of infected carcasses. Three slaughterhouses (Sl) were selected for this study with averages of 200 (SlA), 721 (SlB) and 1138 (SlC) bovines slaughtered per day. The monthly number of slaughtered cattle, infected carcasses with cysticercosis and destination were used to calculate the condemnation occurrence index (COI) and the adjusted seasonal index (ASI). To assess the impact of the legislation, the prevalence rate and destination of infected carcasses were subdivided into the PRE (January 2013 to March 2017) and POST (April 2017 to December 2020) period of Decree 9013 of 2017 and the results were compared by chi-square (P < 0.05). SlA recorded the highest cysticercosis rate with 1.54 % and SlC the lowest rate with 0.33 %. In addition, it was observed that in the POST period there was an increase in the identification of infected carcasses in SlA and B (P < 0.05). The POST period also resulted in a change in the relative frequency of infected carcasses destination in the three slaughterhouses (P < 0.05). The ASI identified an increase in infected carcasses in February and a decrease in November for SlB, proving to be an important tool for planning the inspection team trainings. These results show that the disease is still present in the studied region and highlight the benefits of using the One Health concept in the evaluation of a time series prevalence of bovine cysticercosis by: identifying seasonality of the disease, trends during the time period and impacts brought by updates in the national sanitary legislation.

Destructive and nondestructive procedures to obtain chicken carcass samples for Escherichia coli and Salmonella spp. detection.

Destructive and nondestructive sampling procedures were compared for Escherichia coli and Salmonella spp. detection in 60 fresh chicken carcasses, which were submitted to the following sampling procedures: rinsing, skin swabbing, tissue excision, and skin excision; the proximity or not to the cloacae region was also considered. The obtained results were compared to identify significant differences (p<0.05). Forty eight chicken carcasses were positive for E. coli, and five were positive for Salmonella spp. For E. coli, nonsignificant differences were observed between rinsing and tissue excision, rinsing and skin excision, and skin excision and tissue excision (p>0.05), thus indicating equivalencies between these techniques. Skin swabbing produced a statistically significant lower frequency of positive results (p<0.05) than all other techniques for E. coli, thus indicating its inadequacy for detection of this microorganism. For Salmonella spp., no significant differences were observed between the sampling techniques (p>0.05), possibly due to the low overall frequency of positive carcasses. No significant differences in the number of positive samples (E. coli or Salmonella spp.) were observed between samples collected near or far from the cloacae region (p>0.05), regardless of the sampling technique. The obtained results demonstrate that the tested sampling techniques were equivalent for Salmonella spp. detection in chicken carcasses, as observed for E. coli with the exception of skin swabbing.

Microbiological assessment at slaughter of chicken carcasses from commercial, backyard and semi-backyard production systems.

INTRODUCTION: Smaller scale, alternative, chicken production systems are gaining popularity globally. However, this brings public health and market confidence concerns, especially where there are no established standards of production. The aim of this study was to carry out a microbiological analysis of chicken carcasses from the commercial, backyard and semi-backyard production systems, slaughtered in the same slaughterhouse. METHODOLOGY: Samples of 102 chicken carcasses were taken in two steps of the slaughter (A: after bleeding; and B: after chiller tank) and were subjected to aerobic mesophilic, coliforms at 35 °C and coliforms at 45 °C counts, and Salmonella spp. detection. Salmonella spp. isolates were subjected to antimicrobial resistance analysis. RESULTS: At slaughter step A, carcasses from the backyard system had less contamination than carcasses from the commercial system, with a difference of 0.7 log10 CFU/mL. Salmonella was identified in carcasses of all production systems and in both slaughter steps. Nine chicken carcasses were positive for Salmonella and no significant difference was observed in the occurrence of Salmonella amongst the carcasses from different production systems. Two Salmonella isolates, that presented the highest resistance profiles (one isolate was resistant to eight and the other to six out of ten tested antibiotics), were identified on carcasses from the semi-backyard system. CONCLUSIONS: Carcasses from the backyard system had a lower microbial count at the initial step of the slaughter process than the commercial production system. In addition, greater resistance to antimicrobials was observed in Salmonella isolates from semi-backyard system.

Salmonella spp. and hygiene indicator microorganisms in chicken carcasses obtained at different processing stages in two slaughterhouses.

Chicken meat is considered an important vehicle of foodborne pathogens such as Salmonella spp., demanding an effective control of its contamination during industrial processing. This study aimed to investigate the presence of Salmonella spp. and microbiological indicators at different stages of processing in two slaughterhouses (Sh1, high-capacity; Sh2, low-capacity). Surface samples of chicken carcasses were collected in the following sequential stages: (A) immediately before evisceration, (B) after evisceration, (C) after showering, and (D) after chiller. All samples were submitted for detection of Salmonella spp. and enumeration of mesophilic aerobes, total coliforms, thermotolerant coliforms, and Escherichia coli. The obtained means and frequencies were compared by analysis of variance and chi-square tests (p < 0.05), considering different slaughterhouses and stages of processing. No significant differences were observed between the frequencies of Salmonella spp. obtained at different steps in Sh1 and Sh2 (p > 0.05). Sh2 showed higher levels of microbiological contamination when compared with Sh1 for mesophilic aerobes (in stages B and D), total coliforms and thermotolerant coliforms (stage D), and E. coli (all stages) (p < 0.05). The variation in the levels of contamination by microbiological indicators over the processing indicated the significance of different control procedures adopted by slaughterhouses for the microbiological quality of chicken carcasses.

Glucuronidase activity of Escherichia coli isolated from chicken carcasses.

To identify Escherichia coli through the production of ß-D-glucuronidase (GUD), 622 suspect cultures were isolated from chicken carcasses and plated in Petrifilm™ EC. Of these cultures, only 44 (7.1%) failed to produce GUD. This result indicates the usefulness of GUD production for estimating E. coli populations in chicken.

Microbiological Testing for the Proper Assessment of the Hygiene Status of Beef Carcasses.

Microbiological testing is an important quality management tool in the food industry. In this study, the hygiene status of beef carcasses sampled in eight Brazilian slaughterhouses was assessed by enumeration of different hygiene indicator microorganisms, and a model to establish potential associations among these counts was proposed. The carcasses (n = 464) were surface sampled at four slaughtering steps (step 1: Hide after bleeding; step 2: Carcass after hide removal; step 3: Carcass after evisceration; step 4: Carcass after end washing) and subjected to a counting of mesophilic aerobes (MA), Enterobacteriaceae (EB), total coliforms (TC), and Escherichia coli (EC) using Petrifilm™ plates. Among the sampled beef carcasses (step 4), 32 (6.9%) and 71 (15.3%) presented counts above the microbiological criteria established by (EC) No. 1441/2007 for MA and EB, respectively. Thus, indicating that improvements in slaughter hygiene and a review of process controls are demanded in some of the studied slaughterhouses. The log count differences of EC, TC, and EB from MA were considered as response variables as a function of the slaughtering steps. Differential log counts changed consistently with the steps. The measurements, including the patterns in their inherently random variability, were fairly predictable from steps 1 and 4. The results indicated that differential log counts for TC and EC are not relevant, as their concentrations and random pattern can be inferred from counts of MA and EB. The proposed model can be used as a valuable tool for the design and adoption of feasible quality control programs in beef industries. The adoption of such a tool should have a positive contribution on consumers' health and enhance product quality.

Hygiene and Safety in the Meat Processing Environment from Butcher Shops: Microbiological Contamination and Listeria monocytogenes.

The quality and safety of meat products can be estimated by assessing their contamination by hygiene indicator microorganisms and some foodborne pathogens, with Listeria monocytogenes as a major concern. To identify the main sources of microbiological contamination in the processing environment of three butcher shops, surface samples were obtained from the hands of employees, tables, knives, inside butcher displays, grinders, and meat tenderizers (24 samples per point). All samples were subjected to enumeration of hygiene indicator microorganisms and detection of L. monocytogenes, and the obtained isolates were characterized by their serogroups and virulence genes. The results demonstrated the absence of relevant differences in the levels of microbiological contamination among butcher shops; samples with counts higher than reference values indicated inefficiency in adopted hygiene procedures. A total of 87 samples were positive for Listeria spp. (60.4%): 22 from tables, 20 from grinders, 16 from knives, 13 from hands, 9 from meat tenderizers, and 7 from butcher shop displays. Thirty-one samples (21.5%) were positive for L. monocytogenes, indicating the presence of the pathogen in meat processing environments. Seventy-four L. monocytogenes isolates were identified, with 52 from serogroups 1/2c or 3c and 22 from serogroups 4b, 4d, 4a, or 4c. All 74 isolates were positive for hlyA, iap, plcA, actA, and internalins (inlA, inlB, inlC, and inlJ). The establishment of appropriate procedures to reduce microbial counts and control the spread of L. monocytogenes in the final steps of the meat production chain is of utmost importance, with obvious effects on the quality and safety of meat products for human consumption.

Low occurrence of Listeria monocytogenes on bovine hides and carcasses in Minas Gerais State, Brazil: molecular characterization and antimicrobial resistance.

Listeria monocytogenes occurrence was assessed in three slaughterhouses located in Minas Gerais state, Brazil, by analysis of 209 bovine carcasses. Four sponge samples were obtained from each carcass in different steps (A, from hide, before bleeding; B, after hide removal; C, after evisceration; and D, after end washing), resulting in a total of 836 samples. The samples were tested for the presence of L. monocytogenes according to the International Organization for Standardization 11290-1, and positive results were recorded in steps A (1 of 209) and D (1 of 209) from slaughterhouse 03. L. monocytogenes isolates (n = 5) were identified by multiplex PCR as belonging to serogroup IIc (representing serotypes 1/2c or 3c) and presented identical pulsed-field gel electrophoresis profiles; in addition, the isolates harbored the virulence genes inlA, inlB, inlC, inlJ, plcA, hlyA, actA, and iap and were sensitive to ampicillin, vancomycin, gentamicin, erythromycin, tetracycline, rifampin, chloramphenicol, trimethoprim, and sulfamethoxazole. The obtained data indicated a low occurrence of L. monocytogenes on bovine hides and carcasses from slaughterhouses located in Minas Gerais state, Brazil, and the presence of distinct virulence makers and susceptibility to a variety of antimicrobials by the obtained isolates.

Contagens de bactérias aeróbias mesófilas e psicrotróficas em filés de tilápias comercializados em dois supermercados de Uberlândia-MG / Counting of aerobic mesophilic and psychrotrophic bacteria in tilapia fillets marketed in two supermarkets of Uberlândia-MG

O objetivo do trabalho foi avaliar as contagens de bactérias aeróbias mesófilas e psicrotróficas em filés de tilápias de dois supermercados de Uberlândia-MG. 30 filés frescos oriundos do estabelecimento A e 29 do B foram amostrados por esfregaço superficial (50 cm2) para contagens de bactérias Aeróbias Mesófilas (AM) (Pour Plate -37°C/ 48h) e Psicrotróficas (PSI) (Plaqueamento em superfície – 7°C/ 7dias) em Plate Count Agar. Comparou-se as médias de contagens por Mann-Whitney (P<0,05). Os filés do estabelecimento A apresentaram média de contaminação superior à encontrada no estabelecimento B para AM (5,54 e 3,74 UFC/ cm2 respectivamente) e PSI (7,41 e 5,78 UFC/ cm2, respectivamente). Os altos níveis de contagens indicam a necessidade de melhorias nas boas práticas de fabricação para reduzir a contaminação dos filés comercializados.

Avaliação da adesão às boas práticas de fabricação em estabelecimentos que manipulam carne no município de Uberlândia/MG / Evaluation of the adhesion to good manufacturing practices in establishments that handle meat in Uberlandia municipality / MG

O objetivo do trabalho foi avaliar a utilização de boas práticas de fabricação em açougues localizados em Uberlândia (MG). Foram feitas visitas à seis açougues (A-F) para avaliação dos itens: edificações e instalações; equipamentos, móveis e utensílios; e manipuladores. Os dados foram comparados pelo Teste Exato de Fischer (p<0,05). As não conformidades do estabelecimento D foram maiores que A e B (p<0,05) e dentre as categorias avaliadas a maior frequência de inconformidades foi observada nas edificações e instalações (45,5%). Nesta categoria, a maior frequência de inconformidades apresentou-se na área interna (72,2%), com presença de produtos de limpeza; ventiladores e garrafas d’água. Os resultados indicam a necessidade de maior monitoramento por parte dos estabelecimentos para que possam oferecer produtos com melhor qualidade aos consumidores.

Avaliação do manejo e transporte de bovinos para o abate em Uberlândia-MG / Evaluation of cattle management and transport to a slaughterhouse in Uberlandia-MG

O objetivo do trabalho foi avaliar o processo de transporte rodoviário de bovinos abatidos em um abatedouro-frigorífico da cidade de Uberlândia-MG. Foi avaliado o processo de manejo, embarque e transporte de 502 bovinos encaminhados para o abate e oriundos de 10 propriedades rurais. Falhas no manejo ocorreram em 80% das propriedades avaliadas, já problemas nas instalações chegaram a 60% das propriedades sendo que a má qualidade do embarcador foi o principal motivo de levar animais a quedas no embarque. Apesar do processo de transporte parecer simples, observou-se presença de várias falhas na propriedade, embarque e no transporte até a chegada ao abatedouro, podendo ocasionar aumento do estresse animal e perdas econômicas.

Caracterização do manejo pré-abate de bovinos em um abatedouro-frigorífico de Uberlândia-MG / Characterization of pre-slaughter management of cattle at a Slaughterhouse in Uberlândia-MG

O objetivo deste trabalho foi avaliar o manejo pré-abate de bovinos em um abatedouro frigorífico de Uberlândia – MG, quanto às adequações para um abate humanitário. Foram realizadas 6 visitas ao estabelecimento, onde se coletou informações referentes à 1011 bovinos (uso de choque elétrico, escorregões, quedas, e taxas de lotação dos currais). A primeira visita apresentou a menor proporção de estímulos elétricos por animal (1,56) e a sexta visita a maior frequência (2,98). Os menores valores de escorregão e queda obtidos foram nos currais com frequência respectiva de 1,68% e 0,79%. Não houve relação entre o excesso de animais em um determinado compartimento e o número de quedas, escorregões e choques (p>0,05). O estabelecimento se adequou em partes à legislação, porém, ajustes podem contribuir para a melhor qualidade do manejo.

Frequência, caracterização e fatores associados à ocorrência de fraturas na coluna vertebral de suínos abatidos em Uberlândia - MG / Frequency, characterization and factors associated with occurrence of fractures in the vertebral column of swine in Uberlândia - MG

A ocorrência de fratura em coluna vertebral de suínos representa uma grande preocupação para a indústria pois resulta em condenação de partes da carcaça durante a toalete. Desse modo, o objetivo do trabalho foi avaliar fatores que influenciam a ocorrência destas fraturas em suínos abatidos em Uberlândia-MG. Foram coletadas informações sobre a origem dos animais, peso, conformidade da eletrocussão e localização da fratura de 745 suínos. Do total analisado, 274 (36,8%) apresentaram fratura, em sua maioria na posição medial (80,2%). Dentre os fatores analisados, o único que influenciou a ocorrência de fraturas vertebrais foi a origem dos animais (P<0,05). Conclui-se que a origem dos animais exerce influência sobre a ocorrência de fraturas de coluna em suínos e estudos subsequentes podem ajudar a justificar esta relação.

Antimicrobial resistance and virulence profiles of Salmonella isolated from butcher shops in Minas Gerais, Brazil.

Salmonella can contaminate finished products of butcher shops, mainly through cross-contamination of utensils exposed to raw materials. To identify the main sources of contamination with this foodborne pathogen in four butcher shop environments, surface samples were obtained from employees' hands, cutting boards, knives, floor of the refrigeration room, meat grinders, and meat tenderizers (32 samples per area) and analyzed for Salmonella using the International Organization for Standardization method 6579, with modifications. Suspect isolates were identified by PCR (targeting ompC), and confirmed Salmonella isolates were subjected to pulsed-field gel electrophoresis (after treatment with restriction enzyme XbaI), analyzed for the presence of virulence genes (invA, sefA, and spvC), and screened for resistance to 12 antimicrobials. Salmonella isolates was identified only on cutting boards (five samples) from three butcher shops. Fifteen isolates were confirmed as Salmonella belonging to four pulse types (similarity of 71.1 to 100%). The invA gene was detected in 13 isolates, and the sefA was found in 8 isolates; no isolate carried spvC. All tested isolates were resistant to clindamycin and sensitive to amikacin and cefotaxine, and all isolates were resistant to at least 3 of the 12 antimicrobials tested. The results indicate the importance of cutting boards as a source of Salmonella contamination in butcher shops. The presence of multidrug-resistant Salmonella strains possessing virulence genes highlights the health risks for consumers.

Comparison of destructive and nondestructive sampling techniques of retail chicken carcasses for enumeration of hygiene indicator microorganisms.

The type of sampling technique used to obtain food samples is fundamental to the success of microbiological analysis. Destructive and nondestructive techniques, such as tissue excision and rinsing, respectively, are widely employed in obtaining samples from chicken carcasses. In this study, four sampling techniques used for chicken carcasses were compared to evaluate their performances in the enumeration of hygiene indicator microorganisms. Sixty fresh chicken carcasses were sampled by rinsing, tissue excision, superficial swabbing, and skin excision. All samples were submitted for enumeration of mesophilic aerobes, Enterobacteriaceae, coliforms, and Escherichia coli. The results were compared to determine the statistical significance of differences and correlation (P < 0.05). Tissue excision provided the highest microbial counts compared with the other procedures, with significant differences obtained only for coliforms and E. coli (P < 0.05). Significant correlations (P < 0.05) were observed for all the sampling techniques evaluated for most of the hygiene indicators. Despite presenting a higher recovery ability, tissue excision did not present significant differences for microorganism enumeration compared with other nondestructive techniques, such as rinsing, indicating its adequacy for microbiological analysis of chicken carcasses.

Inspected and non-inspected chilled chicken carcasses commercialized in Viçosa, MG, Brazil: microbiological parameters and Salmonella spp. occurrence / Carcaças de frango refrigeradas inspecionadas e não-inspecionadas comercializadas em Viçosa, MG, Brasil: parâmetros microbiológicos e ocorrência de Salmonella spp

Sixty samples of chilled chicken carcasses submitted (30) and not submitted (30) to Brazilian inspection services were analyzed to investigate if inspected and non-inspected chilled carcasses represented different food safety risks in the region of Viçosa, MG, Brazil. The mean counts of indicator microorganisms (mesophilic aerobes, Enterobacteriaceae, total coliforms and Escherichia coli) of samples belonging to the inspected and non-inspected lots did not present significant differences (P>0.05). Also, no significant differences (P>0.05) were observed for the numbers of Salmonella spp. and E. coli (higher than 2log cfu g-1) between samples submitted or not to inspection. Statistical differences were observed between the two sample classes only for the numbers of mesophilic aerobes higher than 4 and 5log cfu g-1 (P<0.05). The obtained results indicated the limitations of microbiological parameters to differentiate inspected and non-inspected chilled chicken carcasses commercialized in the specific studied area.

Sessenta amostras de carcaças de frango refrigeradas fiscalizadas (30) e não fiscalizadas (30) por serviços brasileiros de inspeção foram analisadas para investigar se carcaças refrigeradas inspecionadas ou não apresentam diferentes riscos alimentares na região de Viçosa, MG, Brasil. As médias de contagens de microrganismos indicadores de higiene (aeróbios mesófios, Enterobacteriaceae, coliformes e Escherichia coli) de amostras inspecionadas ou não inspecionadas não apresentaram diferenças significativas (P>0,05). Também não foram observadas diferenças significativas entre amostras inspecionadas e não inspecionadas com resultados positivos para Salmonella spp. e E. coli (contagens acima de 2log cfu g-1). Diferenças significativas (P<0,05) foram observadas somente entre os números de amostras com contagens de aeróbios mesófilos superiores a 4 e 5log cfu g-1. Os resultados obtidos indicam as limitações dos parâmetros microbiológicas para diferenciar carcaças de frango inspecionadas ou não na região específica onde o estudo foi conduzido.

Glucuronidase activity of Escherichia coli isolated from chicken carcasses

To identify Escherichia coli through the production of â-D-glucuronidase (GUD), 622 suspect cultures were isolated from chicken carcasses and plated in PetrifilmTM EC. Of these cultures, only 44 (7.1 percent) failed to produce GUD. This result indicates the usefulness of GUD production for estimating E. coli populations in chicken.